The present invention relates to can ends having a non-removable tear panel which defines a large opening for improved pour characteristics, so called large opening ends (LOE). In particular, the invention relates to the shape of such large openings in can ends having a reduced diameter centre panel.
Typically, aluminium or steel cans filled with beer, soft drinks or the like are provided with easy open, stay on tab type ends having a non-removable tear panel which is torn and swung down into the can to provide an opening through which the contents of the can may be dispensed. The opening provided in conventional cans is generally small and as a consequence it is not possible to pour the contents from the can in a smooth manner because the liquid tends to be dispensed in small spurts or glugs. This is particularly difficult where the contents are being drunk directly from the can as the glugs mean that the liquid has to be sipped.
Can ends having larger openings have been proposed, for example in U.S. Pat. No. 5,711,448, in order to improve pourability and drinkability. This improved performance is usually obtained by providing openings of larger area than the conventional openings discussed above. The pour characteristics of these large openings allow the contents of the can to be dispensed at higher flow rates than conventional openings, with fewer spurts or glugs. This allows the contents of a can to be drunk directly from the can, in a more natural manner.
Can ends are made in a variety of sizes from 202 to 211 (using conventional can makers' terminology). However, there is continual pressure to reduce the size of can ends. Recently, 206 ends were conventionally used for all beverage cans and these size ends are still used on the majority of beer cans in Europe. However, on cans for soft drinks, 202 ends are now the industry standard in both the US and Europe and there is industry pressure to reduce the remaining 206 ends to 202 ends. Thus, cans are being produced with successively smaller diameter ends in order to provide cost savings through lightweighting.
Furthermore, it has been proposed to reduce the diameter of the centre panel of the can end whilst retaining the nominal can end diameter, as discussed in WO 96/37414. Such can ends have an outer circumferential “hook” which is separated from a smaller diameter centre panel by an inclined side wall. The side wall is inclined at an angle of between 20° to 60° to the plane of the centre panel.
As centre panels become smaller (either through reducing the size of the can end or through the use of inclined side walls) it becomes more difficult to provide an opening having the area considered necessary to obtain improved pouring and drinking performance, due to the reduced distance between the rivet and the side wall of the end panel.